same new member here...
this analogy maybe ll help you...
which one do you think is greater, the brand new car that hasn't been modified or the modified car that its components, including engine, brake, and body has been modified into the best one???...
when you play NFS or GT sure you ll upgrade your car components, right?
same like the custom rom compared to the stock...
even the stock has a lot of problems..
here mine when i bought, i got nothing special with my gio with 2.2.1 stock FW
even the galaxy mini is better comparing to gio with the stock in GPS test
so u better root you phone, without being care about the MOdulator-DEModulator stuff and going to new custom rom
there are a lot of Best rom in the Android Development forum like the one created by phiexz, search yourself
to have custom rom sure you have to root your device, and don't think it's complicated that you should get other's help
u can do yourself
1.)search the root tutorial based on your current rom (when i first root my phone i used superoneclick, but if it's kinda complicated, seach another way)
2.)then install Clockworkmod Recovery, download in the market or else by the name ROM Manager (or the customized CWM)
3.)download the rom (complete components, if existed)
4.)flash the rom by rebooting into recovery... (don't care about rooting again, u ll find most of the rom will be automatically rooted with new CWM, and a2sd enabler)
5.)short tutorial above depends on the rom you ll be flashed
i'm a bit being advisor, hope u dont mind...